1. Field of the Invention
This invention relates to support structures and more particularly to a structure for erecting sections of scaffolding at a construction site and relocation of the completed scaffolding as required.
2. Prior Art
Scaffolding allowing work to be performed at elevated heights has been used for many centuries. For example, in the early 1500's Michelangelo painted the ceiling of the Sistine Chapel while allegedly supported by scaffolding.
In modern times scaffolding typically is formed by joining a series of scaffold sections together. Each section comprises a pair of spaced apart end frame units made from integrally joined tubular members. The end frame units then are connected by cross bracing having a tubular or bar form. Connection between such promote ready assembly and disassembly.
When disassembled, the end frame units and cross bracing may be loaded onto a truck and moved to another location for reuse. U.S. Pat. No. 3,915,303 discloses apparatus for tying together a series of scaffold end frame units. The apparatus and included end frame units then may be handled and moved more easily.
A length of the scaffold may be increased by merely connecting additional horizontally positioned sections. Two adjoining sections share a common end frame unit. Wooden planks placed on upper cross pieces of the end frame units form an elevated work platform.
A height of the work platform may be increased by adding further sectional tiers progressively on top of the lower sectional tiers. These tiers, interconnected with ladders, allow workmen to ascent to heights several hundred feet above ground level. U.S. Pat. Nos. 2,379,446 and 2,555,782 disclose typical forms of scaffold structure.
An a typical scaffold is set out in U.S. Pat. No. 2,598,730. This structure has a C-like shape defined by spaced apart upper and lower horizontal portions connected by an upright section. The structure is portable allowing its selective movement by a forklift truck under an upper deck of a pier. The truck first lifts the structure and then moves it to a position beyond an edge of the pier. Next, the truck lowers the structure until the lower horizontal portion is below the pier upper deck. Lastly, the truck moves in a reverse direction to position the lower portion under the deck. This lower portion then forms a work platform.